In the construction of installations, it is necessary to provide a large number of appliances in the individual parts of the installation with supply lines. These supply lines can be electrical lines, hydraulic lines, air-pressure feeds, data lines and any other kind of connection or supply line that is needed for operating the appliance in the installation.
Furthermore, it is necessary to occasionally insert and remove an appliance of this kind. Such occasions may arise, for example, when servicing an appliance, or when replacing a defective appliance. Under these circumstances, the appliance to be removed may be in a fairly inaccessible location within the installation. This can make the removal of such an appliance complicated.
An additional problem that arises is that the connecting or supply lines are relatively short in the region of the insertion or removal apertures. As a result, before the appliance can be taken out or re-inserted, these lines have to be attached or detached while still at the location at which the appliance is being operated. This can be difficult because one may have to work in cramped quarters.
In order to solve this problem, it is known to provide spare lengths of line in the region of the appliance and of the insertion aperture. By this means, the appliance can be taken out without having to immediately disconnect the line. In the case of simple servicing operations, these lines can even remain on the appliance under certain circumstances. By avoiding the need to attach and detach supply lines, one can considerably shorten the servicing time. Even when a supply line has to be detached from the removed appliance and connected again after the repair, having a spare length makes this part of the servicing operations considerably easier.
In practice, however, it has turned out that during installation, it is quite common for installers not to provide spare lengths of line. A natural tendency among installers appears to be to pull the line taut when it is laid. This results in either a non-existent spare length of line or one that is too short to be useful. Depending upon the way in which the appliance is designed, moreover, it is difficult to guide the spare lines without their becoming twisted. In some cases, the spare length may even impair operation of the appliance.